The Art of Integrated Functionalization: Super Stable Black Phosphorus Achieved through Metal-Organic Framework Coating

Black phosphorus (BP) is a promising 2D nanomaterial with a great potential in various areas, while its intrinsic instability greatly suppresses practical applications, particularly under harsh conditions (e.g., high temperature). Herein, BP functionalization with Al ion is achieved in an integrated manner through MIL-53 metal-organic framework (MOF) coating, which greatly improves both ambient and thermal stability of BP. For the obtained MIL-53 coated BP (BP@MIL-53), abundant Al ion within MIL-53 interacts with the lone pair electrons of BP, and subsequently decreases the BP surface electron density, reducing the reactivity of BP toward O-2 and H2O. The MOF growth crosslinks the Al ion on the BP surface, and achieves integrated functionalization to withstand the detachment of individual Al ion from the BP surface. The noncovalent bond of BP-Al and highly porous structure of MIL-53 preserve the physical/chemical properties of BP to the maximum, and render BP@MIL-53 with super-stability. This functionalization strategy extends the applications of BP based devices under high temperature conditions. As a proof of concept, BP@MIL-53 is further utilized as a NO2 gas sensor under relatively high operating temperatures. The BP@MIL-53 sensor exhibits fast response, outstanding selectivity, and high recovery dynamic process in contrast to bare BP sensor.